Heretofore various signs have been constructed for receiving removable letters, numbers, etc. These have included sign faces wherein the letters have been secured by various means, such as by metal clips, screws, by inserting the edges of the letters into variously shaped channel members which normally hold the letters on the sign face. However, many of the former signs have had problems retaining the letters on the sign face. Frequently, such letters would blow off of the sign, particularly if it was a trailer-mounted sign and pulled from place to place. Also, as the letters are relatively expensive, their loss is both an expense as well as a nuisance. Many of the former sign board constructions have required letters having specially shaped tangs or connecting members for connecting them to the sign face.